Five Things You Should Know About…Tires

March 4, 2011
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Edvald Boasson Hagen puts a lot of faith in his tires and he takes a fast corner while looking cool and collected.
(Photo: Yuzuru Sunada)


Historians maintain that the first commercial vehicle to be outfitted with pneumatic tires was the bicycle. Over 150 years later, an air-filled tube of rubberized cloth remains the most efficient way to roll down the road-for autos, airplanes and even the lowly bicycle. This month, RBA takes aim at five tidbits that every cyclist should know about tires.
There is a reason why ProTour racers insist on handmade tubular tires that cost upwards of $100. Everything that goes on between the rider and the road is filtered through the tires. You don’t need to ride glued-on tubular tires to reap the benefits of great-rolling rubber, but buy the best you can afford. Good tires use flexible casings made with fine-thread fabric, and the tread is thinner and compounded with resilient rubber. Cheap tires feel dull and disconnected. Nothing you can do to your bike will affect its feel and performance more than your tire choice.

The fastest racing tires have a thin tread over a supple, lightweight casing. Slick tread tires, like the Hutchinson Atom, offers a superior ride in both wet and dry conditions.
The sport’s greatest minds once espoused that the only way to lower a tire’s rolling resistance was to increase the air pressure. They were nincompoops. We now know that the best rolling tire must be able to seamlessly deflect and then return to its shape as it rolls over each of the pavement’s countless irregularities. Over-pressurized, bouncy tires convert precious forward movement into wasted upward acceleration- millions of times a minute. Get the air pressure right and your tires will feel firm when you climb or sprint, corner with more traction, and roll smoothly with the lowest possible rolling resistance. Air molecules constantly slip through the walls of the tire and tube, so check your tire pressure every time you ride.
Here’s a tip: Optimum tire pressure is related to three factors: tire stiffness, the diameter of the tire casing, and the weight of the rider. Each tire has its sweet spot, so experiment by starting at the tire’s recommended maximum pressure and then reducing it in 5psi increments until the wheels begin to roll smoothly and don’t chatter over rough pavement. Use about 3 to 5psi more in the rear tire.

Get the pressure right and your tires will roll faster over rough pavement. If the wheels are bouncing, you are wasting energy and losing forward momentum.

Any adult with functional appendages can fix a flat tire (we’re talking clincher tires here). Put the cell phone back in your jersey, pull out the spare tube and man up. Two universal mistakes defeat amateur flattire- fixers: Mistake number one is failing to completely release the tire’s bead and ensure that it sets into the rim’s central depression before attempting to remove or install the tire.
The second mistake is beginning or ending the process opposite the valve stem. The ‘rim well’ (the low section in the center of a clincher rim), is designed to give the tire bead enough free play to hoist it up and over the rim-but you have to get most of the bead into the well for this to happen. The valve stem prevents some of the bead from dropping into the rim well and thus prevents the tire from being removed or installed  easily (or at all). When you begin the process, work around the rim, pinching the bead into the well while lifting the tire near the valve stem. Begin removing, or finish installing, the tire about two inches to the right or left of the valve stem.

If you get caught on the side of the road with a stubborn tire and have no tire levers handy, remove your quick release skewers and use the ends as tire tools.

Tubeless tires are gaining momentum-and for good reason: they roll faster than the best clinchers, feel smoother over rough roads and rarely pinch flat. If you choose tubeless (and we think this is the future of pneumatic bicycle tires), add an ounce of liquid sealant to get the full benefits of the system. You’ll have to cut a tire to get a flat, and your tires will hold pressure longer. Tip: Tubular tire users can extend the life of their tires by injecting some liquid sealant into the tubes. The valve core must be removable, and add sealant before the puncture, because the tube and tire will be lined up tightly against the puncture-which creates a better seal.
Bonded-in anti-puncture layers used to add significant weight to a tire, but not today. Many elite-level racing tires incorporate tightly woven Vectran or Kevlar cloth beneath the tread to ward off sharp objects. It works, so invest in tires with anti-puncture technology and you’ll ride safer and happier. Tip: Don’t fall for the “heavy tubes are less prone to punctures’ theory. Lightweight tubes roll faster and make the tire feel livelier. If a thorn is sharp enough to get through the tire, it will have no problem continuing on through a wimpy layer of unreinforced rubber.

Protective layers of Vectran or nylon fabric molded under the tread are quite effective in warding off sharp objects like glass shards and thorns – as the Schwalbe puncture test dramatically shows.


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